Apache SpamAssassin is a suite of open source spam filtering software that provides system administrators with a filter to categorize email and block spam (unsolicited bulk email). It also uses a powerful scoring framework and plugins to integrate a variety of advanced heuristic and statistical analysis tests on email headers and bodies, including text analysis, Bayesian filtering, DNS blacklists, and collaborative filtering databases. In addition, Apache SpamAssassin has a modular architecture that can be quickly integrated with other projects.

The recently released 4.0 is a major update with many improvements and new features compared to the SpamAssassin 3.4 series.

Some highlights are as follows

• Full Unicode character support and native UTF-8 handling now make it easy to stop spam in different languages
• better geolocation
• Improved Bayesian filtering, especially around non-English emails and common words
• Improved SSL client certificate support
• Introduced new plugin for checking email compliance with DMARC policies after parsing DKIM and SPF results
• Introduces a plugin capable of decoding shortened URLs from various URL shortening services.The plugin will figure out the real URL from supported URL shortening services to check for spam related matches
• The ExtractText add-in allows calling external software to extract text from email attachments, such as PDF or Microsoft Office documents, etc. Tesseract OCR can also be used to analyze text on images
• Other bug fixes, optimizations, etc.

The official team said that this version integrates the corrections of the past few years, significantly improves classification and performance, and has been fully tested in a production environment. Users are strongly recommended to upgrade as soon as possible.

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